This invention pertains to lubricant compositions for finishing synthetic fibers and more particularly to such compositions containing propylene oxide/ethylene oxide block co-polymer adducts of aliphatic monohydric alcohols having 6 to 14 carbon atoms as emulsifiers.
During the conventional manufacture of synthetic continuous filament yarn, such as polyamides and polyesters, the yarn is treated with a lubricating composition usually in the form of an aqueous emulsion. Such compositions normally contain a lubricant, such as, fatty acid esters, hydrocarbon oils, and/or vegetable oils, an anti-static agent, an anti-oxidant and an emulsifier system to render the lubricant composition water emulsifiable. The complete lubricant composition should serve the processing and manufacturing needs of the fiber producer as well as the user of the synthetic yarn. The lubricant composition provides controlled lubricity (frictional properties) during yarn processing by high-speed machinery, provides proper yarn intra-frictional properties, and protects the yarn from damage during manufacturing and processing handling requirements.
For high-speed and high-temperature yarn processing, such as, hot-stretching, bulking, crimping and texturizing, the lubricant composition must function adequately at both ambient and high temperatures. In addition to the aforementioned requirements, the lubricating composition must exhibit special qualities for high-temperature processing, that is, the composition should be sufficiently stable so as not to smoke or fume nor result in the formation of varnishes or resins upon deposition onto machinery-heated surfaces. In order to meet the thermal requirements, each component of lubricating composition should possess the necessary thermal stability. However, in actual practice only some of the components fulfill the thermal prerequisites. In particular, some emulsifier systems fail to meet the thermal stability standards because of the chemical make-up of the emulsifier or emulsifiers which is designed to produce stable aqueous emulsions of lubricant composition. High fuming or smoking and/or varnish formation upon exposure to high temperature also are normally encountered with conventional surfactant used to formulate the emulsification systems. In addition, the necessity of employing more than one surfactant to achieve stable aqueous emulsions complicates the situation.
Commonly used surfactants such as alkylphenol ethoxylates, sorbitan ethoxylate esters, (hydrolyzed) vegetable oil ethoxylates, alkyl alcohol ethoxylates, fatty acid ethoxylates, and the like, do not meet all the requirements of an emulsifier in a lubricant composition for synthetic yarn. For example, the sorbitan ethoxylate esters and the (hydrolyzed) vegetable oil ethoxylates, although good emulsifiers, produce high amounts of thermo-oxidation varnishes and are high-viscosity components, a factor which is undesirable due to the direct relationship between viscosity and friction. The alkyl alcohol ethoxylates produce large amounts of smoke and require complicated combinations of surfactants to yield stable lubricant composition emulsions. The alkylphenol ethoxylates are good low-fuming emulsifiers, but create unacceptable varnishes. Compared to the other nonionic surfactants listed above, the alkylphenol ethoxylates display the best overall properties as lubricant components for synthetic yarn. Moreover, in copending application Ser. No. 25,663 filed Mar. 30, 1979, now U.S. Pat. No. 4,252,528 (Decker et al.), lubricant compositions containing a particular propylene oxide/ethylene oxide block copolymer adduct of alkylphenol is shown to exhibit acceptable high temperature and emulsifier characteristics. However, it has been found that such surfactants have a viscosity that may be less desirable for some applications and it may also be desirable from an environmental standpoint to employ surfactants that are not phenol containing.
It is therefore an object of this invention to provide synthetic yarn lubricant compositions containing emulsifiers which display the proper thermal stability, low fuming characteristics and emulsification versatility. It is a further object of this invention to provide a single non-phenol-containing surfactant having acceptable high temperature stability and resistance to varnish formation upon exposure to heated surfaces and which will emulsify conventional lubricants used in high-temperature processing of synthetic fibers.
A still further object of this invention is to provide surfactants which produce microemulsions with conventional high-temperature process lubricants.
An indication of the fuming tendencies of a substance is obtained by the measurement of the smoke point.